Genomic PCR of the TWisallele ETn element insertion and identification of wild type T versus TWisallele transcripts. A. Primers F3 and ETn1 were used to amplify a portion of the TWisallele ETn element. T allele genotype of template genomic DNA is indicated above the lanes. As expected, no product was amplified from T +/+ control samples. Brackets indicate bands excised, purified, and sequenced. Ladder = 100 bp DNA ladder, with sizes indicated to right. B. RT-PCR analysis of T +/+, TWis/+, and TWis/TWise8.5 embryo RNA. Genotypes of embryos are indicated above the lanes; - cont = no RNA negative control. Primer pairs used to amplify the product are indicated to the right (see also Table 1). Brackets indicate bands excised, purified, and sequenced. Products were named based on the RT-PCR primer set followed by the lower case letter next to the bracket (see Table 2).